1. Field of the Invention
The present invention relates to the art of forming a knot of threads when carrying out suturing inside living bodies, and in particular relates to knot-forming instrument and method for forming a knot of threads used when tissue is sutured or when anastomosis or ligation is carried out inside an abdominal cavity during, for example, laparoscopic surgeries.
2. Background
In recent years, surgical operations such as appendectomies, gall bladder removals and the like have been performed by laparascopic methods that allow such operations to be carried out without the need to cut open the abdomen. To carry out such laparoscopic surgeries, a plurality of tubes known as trocar tubes are inserted into the abdominal cavity. Various instruments are inserted through these trocar tubes, including a camera that allows a surgeon to carry out the operation while viewing a monitor.
However, when suturing or ligation is carried out with current surgical instruments, it is a very time-consuming process. Stated more concretely, in order to form the suture or ligation, the thread must be pulled out with forceps or the like through one of the trocar tubes to the outside of the body in order to form a knot, which then must be passed back through the trocar tube to place the knot where it needs to be inside the abdominal cavity.
As a result, the operation becomes excessively laborious and time-consuming, and there is also the increased chance of infection.
In recent years, special instruments have been developed in the hopes of eliminating such problems. One example is the staple-type needle proposed by Laid-Open Patent Publication No. 3-12126 for carrying out anastomosis or suturing. However, there is the disadvantage that the staple is likely to be left inside the body. Further, there is also a danger that the stapler can be dropped inside the abdominal cavity due to faulty operation. Moreover, the stapler is not as strong as certain types of thread that could be used for suturing.
Furthermore, during standard surgical operations that require especially strong knots, such as when a thick blood vessel is to be ligated, it becomes necessary to wrap the thread 2 or 3 times. However, the staple means mentioned above cannot be employed for forming such knots. Moreover, to carry out such procedures with existing methods as descsribed above will result in the operation becoming even more laborious and time-consuming.